Objectives: To apply the early receptor potential to the study of genetic and other ocular disease. Methods: A Ganzfeld ERP stimulator will be constructed. The regeneration curves of the early receptor potential will be fractionated mathematically into rod, cone and photostable components. The time constants of regeneration for each component will be determined. Disturbances of these parameters which may be found in tapeto-retinal and other retinal diseases will be investigated. It is planned that this technique will be applied to a variety of retinal diseases of clinical significance, where the pathogenesis is unknown.